Of light interference (e.g., interferometer)

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356280500

Of light interference (e.g., interferometer)

52

20110116074

Measurement of Speed or Vibration Characteristics Using a Lidar Device with Heterodyne Detection - A process for measuring speed or vibration characteristics using a LIDAR device allows the separation of a useful contribution and an interfering contribution in a backscattered signal. To this purpose, a phase characteristic of an optical wave emitted in the direction of a target volume is modulated. The interfering contribution, which originates from a source at a distance from the target volume, appears with variable shifts of said phase characteristic in a heterodyne detection signal. An accumulation then isolates the useful contribution, from which a result is obtained for the speed or vibration measurement. The process can be implemented with a frequency modulation or phase modulation of the optical wave.

05-19-2011

20160131676

SYSTEM AND METHOD FOR MEASURING DOPPLER EFFECT UTILIZING ELASTIC AND INELASTIC LIGHT SCATTERING - Method and apparatus for measuring a Doppler effect of a scattered light include: projecting an ultra violet (UV) light towards a target by a light emitter; receiving the UV light scatter from the target from the emitted UV light reflected from the target by a light receiver; measuring the frequency shift of the UV light scatter with respect to the emitted UV light to obtain distribution of line of sight velocity of macroscopic matters of the target corresponds to a Doppler shift; processing the distribution of the line of sight velocity to determine the Doppler effect of the UV light scatter; and separating the wind line of sight velocity as the centroid shift of the microscopic Doppler shift probability distribution.

FIBER OPTIC SENSOR AND METHOD FOR DETECTING SHOCK WAVE PRESSURE AND MASS VELOCITY IN SOLID MEDIA - A fiber optic pressure and mass velocity sensor for measuring a shock wave pressure in a solid media includes an optical fiber having a means for measuring a change in an optical path length (OPL) of the fiber when positioned in the solid media caused by the shock wave altering the physical length of the fiber and the refractive index of the fiber. The means for measuring the change in the OPL is coupled at one end to a laser and at its second end to a means for detecting the change in OPL. The sensor has a high operating bandwidth (>>10 MHz), is sufficiently rigid to withstand the force of the shock wave, has a sensitivity that can also be tailored for the application, and is immune to electromagnetic interference. Measurement can be made on materials under extreme strain conditions, and the sensor can also provide characterization of protective materials such as bullet/blast proof materials.

11-12-2015

20110019177

FIBER-OPTIC TRANSDUCER FOR FLUID AND/ OR GAS VELOCITY MEASUREMENT - This useful model relates to fiber-optic fluid/gas flow rate measurement transducers and is employed in gas/fluid flow measuring systems, and can be used for water or natural gas consumption monitoring, especially in measuring systems intended for fluid/gas flow monitoring in pipelines and oil/gas wells. The transducer includes optic fiber which comprises at least one Bragg's fiber lattice, wherein the said Bragg's fiber lattice is fitted with at least one concentrator of mechanical stresses which originate in the optic fiber during its interaction with the gas/fluid flow. As a result, the transducer sensitivity increases.

NON-CONTACT OPTICAL FLOW MEASUREMENTS - A method and apparatus are provided for non-contact optical flow measurement in a pipe, the apparatus having one or more modules configured to sense light that is scattered off several points longitudinally along a wall of a pipe having a medium flowing therein and to provide a signal containing information about a deflection of the wall of the pipe that can be used to determine a parameter related to the medium flowing in the pipe, including a flow rate of the medium. The deflection in the pipe wall is caused by a turbulence induced pressure fluctuation which in turn induces a localized pipe wall deflection.

11-04-2010

20110007301

DEVICE AND METHOD FOR MEASURING PARTS - A device and method for measuring moving material includes a processor and operating software associated therewith; a light source for emitting at least two polarized light beams in a manner wherein the beams cross thereby creating an interference region and generate a set of fringes; a sensor aligned relative to the interference region wherein the fringes have a predetermined orientation to the directional movement of the material and wherein the sensor is operably equipped to receive scattered light emanating from the interference region and provide a time varying signal to the processor such that the processor can manipulate and convert the signal to speed and distance and a polarizing filter operably associating a polarizing filter with one of the sensor and the emitting means in a manner to substantially preclude reflected polarized light from the interference region back to one of the sensor and the emitting source.

01-13-2011

20130215411

Velocity Measuring System - A laser Doppler velocimeter uses self-mixing amplification of backreflections from scatterers below the surface of a flow. A time domain signal is divided into segments that are roughly equal to a transit time of particles through a focus of a laser beam. The segments are connected to a frequency domain through the use of an FFT algorithm to produce frequency domain data segments. Signal-to-noise ratio is enhanced through signal processing techniques using the segments to produce a final enhanced signal spectrum.

08-22-2013

20100290030

SENSOR DEVICE AND METHOD FOR DETECTING THE MOTION OF A VEHICLE - A sensor device for detecting a motion state of a motor vehicle. The sensor device includes at least one laser unit having a light source for emitting coherent light which is transmitted in the direction of a roadway surface, and an interference detector which is designed to detect at least one measurement variable which characterizes interference between the light scattered at the surface and the light of the light source. The measurement variable represents a speed component of the sensor device and/or a distance between the sensor device and the roadway surface. The laser unit is coupled to an evaluation device which is designed to determine, from the measurement variable, at least one variable which characterizes the motion state of the vehicle, in particular a speed component of the center of gravity of the vehicle, a rotational angle or a rotation rate of the vehicle.

11-18-2010

20150331004

VELOCITY INTERFEROMETER FOR ANY REFLECTOR WITH VARIABLE SENSITIVITY RANGE AND TIME RESOLUTION - The present disclosure relates to a velocity interferometer. The interferometer described herein, comprises of two optical cells, one partially containing a liquid. The light entering the interferometer is amplitude split and made to propagate through the two cells in such a way that the apparent path lengths of the beams are equal, thereby fulfilling the condition necessary for obtaining single wide fringe in the interference pattern of the two beams. However, due to difference in the physical path traversed by the two beams, a finite delay time exists between them. The two beams, after reflection from end-mirrors or cube corner prisms in the two cells are recombined to form interference fringe patterns on active areas of multiple detectors. Doppler shifted light resulting from reflection of light from a moving projectile generate fringe shifts on the detector planes thereby producing voltage signals proportional to instantaneous velocity of fast moving projectile. The voltage signals are recorded with multi-channel digital oscilloscope and processed in a processor/controller of a computing unit to obtain velocity time history of the projectile. Controlled motion of the cube corner reflectors placed at the ends of two cells using stepper motors and piezoelectric actuators ensures that the time delay between the interfering beams is controlled accurately thereby changing the sensitivity range and time resolution of the velocity measurements.

11-19-2015

20100277715

Optical Air Data Systems And Methods - A method for remotely sensing air outside a moving aircraft includes generating laser radiation within a swept frequency range. A portion of the laser radiation is projected from the aircraft into the air to induce scattered laser radiation. Filtered scattered laser radiation, filtered laser radiation, and unfiltered laser radiation are detected. At least one actual ratio is determined from data corresponding to the filtered scattered laser radiation and the unfiltered laser radiation. One or more air parameters are determined by correlating the actual ratio to at least one reference ratio.

11-04-2010

20110043786

METHOD OF MEASURING THE VELOCITY OF AN AIRCRAFT BY LASER DOPPLER ANEMOMETRY - Method of measuring the velocity of an aircraft at a given instant, by laser Doppler anemometry, by performing the steps of acquiring a backscattered signal on at least three oriented line-of-sight axes, and calculating the spectrum of the backscattered signal on each of the line-of-sight axes. Further, acquiring an additional backscattered signal on at least one additional line-of-sight axis (X

02-24-2011

20100110414

SYSTEM, METHOD AND COMPUTER-ACCESSIBLE MEDIUM FOR TRACKING VESSEL MOTION DURING THREE-DIMENSIONAL CORONARY ARTERY MICROSCOPY - Exemplary embodiments of apparatus, method and computer accessible medium can be provided which can facilitate a determination of at least one characteristic of a structure. For example, it is possible to use at least one first arrangement which can be structured to provide at least one first transmitted radiation along a first axis and at least one second transmitted radiation along a second axis. The first and second transmitted radiations can impact the structure and generate respective first and second returned radiation. The first and second axis can be provided at a predetermined angle with respect with one another which is greater than 0. Further, at least one second arrangement can be provided which can be configured to receive data associated with the first and second returned radiations, and determine at least one relative velocity between the structure and the first arrangement along the first and second axes.

05-06-2010

20100195089

WIND VELOCITY MEASUREMENT SYSTEM AND METHOD - A wind anemometer comprises a light source for transmitting pulsed light signals, a receiver for receiving backscattered signals from airborne particles for each pulse of the transmitted pulsed light signals, a detector for detecting the received backscattered signals, and a processor to determine location of the airborne particles with respect to the anemometer based on the detected backscattered signals. The processor estimates wind velocity using changes in location of the airborne particles over at least one time interval.

08-05-2010

20110222048

DOPPLER ASYMMETRIC SPATIAL HETERODYNE SPECTROSCOPY LIGHT DETECTION AND RANGING RECEIVER - Obtaining global tropospheric vertical wind profiles by directly detecting atmospheric winds using space borne, airborne and/or ground station platforms is accomplished by a DASH interferometer in the back-end of a Doppler wind LIDAR. In the front-end of the Doppler wind LIDAR, a laser illuminates an atmosphere and a telescope collects backscattered laser light return signals from the laser illuminated atmosphere. The DASH interferometer processes return signals from the atmosphere, forming an interferogram and determines from the interferogram a Doppler shift of the return signals, which is equivalent to determining the line of sight wind speed of the Doppler wind LIDAR observation, by measuring the frequency shift caused by winds. From this determination, global and/or non-global atmospheric wind profile data are transmitted over a communications network in either real-time and/or non-real-time, to facilitate weather forecasting, weather modeling, weather avoidance navigation, atmospheric research, hurricane warnings, operations systems selections and deployment of operational assets.

09-15-2011

20140063484

Optical Velocimetry Systems and Methods for Determining the Velocity of a Body Using Fringes Generated by a Spatial Light Modulator - A velocimetry system for measuring the velocity of a moving body propagating through a measurement volume includes a light source for emitting a light beam, a controller for generating a modulation pattern corresponding to a desired set of fringes to be generated in the measurement volume, and a spatial light modulator operatively connected to the controller to receive therefrom the modulation pattern. The spatial light modulator is configured to spatially modulate the light beam according to the modulation pattern in order to generate the desired set of fringes in the measurement volume. Also provided are a light detector for measuring the energy of the light scattered by the moving body as it intersects the fringes, and a data analysis unit operatively connected to the light detector and adapted to determine the velocity of the moving body from at least one fringe characteristic and the energy of the scattered light measured.

03-06-2014

20130162976

High Power Laser Doppler Velocimeter With Multiple Amplification Stages - Systems and methods for laser based measurement of air parameters are disclosed. An example system includes a source of radiation, an amplification system with one or more power amplification stages, a transceiver, and an optical mixer. The source produces a plurality of beams, and the amplification system is configured to amplify the beams. The transceiver is configured to transmit the modulated beam to, and receive a scattered beam from a target region. The optical mixer is configured to determine a difference between the scattered beam and a reference beam, which is used to determine a Doppler shift therefrom. In certain embodiments, the amplification system includes a fiber preamplifier and one or more fiber power amplifiers stages.

Gas Velocity Sensor - A method and apparatus for determining gas velocity, which includes generating transmitted radiation having an expected transmission frequency, detecting backscattered radiation, and determining gas velocity in dependence upon any Doppler shift of the frequency of the backscattered radiation, determining a transmission frequency of the transmitted radiation; detecting any difference between the measured transmission frequency and the expected transmission frequency and generating a feedback signal therefrom, and determining gas velocity using said feedback signal.

07-08-2010

20100085557

Method and arrangement to determine a wind-speed - A method and an arrangement are provided to determine the speed of the wind, which acts on a wind-blade of a wind-turbine. An optical-signal with a known frequency is sent from an optical-transmit-unit to a joint measurement volume. The optical-signal is scattered and reflected by atmospheric particles of the joint measurement volume. The optical signal is shifted in its frequency due to the Doppler-principle, too. The frequency-shifted optical signal is received by a receive-unit. The frequency-shifted optical signal is compared with the sent optical-signal to determine the wind-speed based on the shifted frequency, which is caused by the atmospheric particles.

04-08-2010

20100134780

Biaxial Laser Anemometry Probe - The subject of the present invention is a laser anemometry probe for optical homodyne detection of frequency offset by Doppler effect, comprising two devices (DERF

MULTISCALE DISTANCE MEASUREMENT WITH FREQUENCY COMBS - The invention relates to a method and a corresponding apparatus for measuring distance and optionally speed, in particular for multiscale distance measurement. The method comprises generating a first and a second frequency comb signal (

COLORED NOISE REDUCTION METHOD AND DEVICE FOR OPTICAL REMOTE AIRFLOW MEASUREMENT APPARATUS - A colored noise reduction method for an optical remote airflow measurement apparatus, which emits laser light into the atmosphere as a transmission signal and measures a wind speed of an airflow in a remote region on the basis of a Doppler shift amount of a frequency between the transmission signal and a reception signal, includes: considering a signal strength of scattered light to be substantially non-existent in a remotest region and beyond; calculating a noise distribution by performing processing to average the signal strength in respective Doppler frequency components divided at intervals of a certain frequency in the remotest measurement region and beyond, and performing subtraction processing in each of the Doppler frequency components on all signal strength distributions of the measurement region, which are obtained by dividing the noise distribution at intervals of a certain distance.

04-11-2013

20100134781

SYSTEM AND METHOD FOR MOTION BASED VELOCITY DISCRIMINATION FOR DOPPLER VELOCIMETERS - A Doppler velocimeter apparatus that may have a coherent light source for generating a beam of coherent light. A modulating subsystem may receive and modulate at least a first portion of the beam of coherent light to form a first beam portion, the first beam portion forming a frequency offset and being a modulated, coherent optical signal. An optical element may receive the first beam portion and direct the first beam portion at a subject, the first beam portion being reflected from the subject to form a reflected beam that has a frequency that is modified in relation to the motion of the subject. A processing subsystem may receive a second portion of the beam of coherent light, and also the reflected beam, and uses the second beam portion and the reflected beam to determine a Doppler shift of the reflected beam.

06-03-2010

20140333919

APPARATUS AND METHOD OF MEASURING WEB FEEDING VELOCITY BY USING SINGLE FIELD ENCODER - The present invention relates to a method of measuring web feeding velocity by using an encoder. A method of measuring feeding velocity of a web, on which a scale having a different pitch from a pitch of a mask is formed, includes: calculating a number of vibrations of a moiré image of light passing through the mask and the scale; calculating scale pitches of the fed web based on the calculated number of vibrations of the moiré image; averaging the pitches so that a change in a pitch between adjacent timings among the calculated scale pitches is minimized; extracting first signals corresponding to a plurality of phases for one pitch based on the averaged pitch; calculating second signals for forming a Lissajous circle from the signal corresponding to the plurality of phases; and calculating an angle of the Lissajous circle by the second signals for forming the Lissajous circle and then calculating the feeding velocity of the web by using the calculated angle.

11-13-2014

20150015869

LADAR BACKTRACKING OF WAKE TURBULENCE TRAILING AN AIRBORNE TARGET FOR POINT-OF-ORIGIN ESTIMATION AND TARGET CLASSIFICATION - A weapon-locating ladar system estimates a backward trajectory of an airborne target by using flow field measurements to follow the wake turbulence trailing the airborne target from a position at which the target is detected backwards until the wake is no longer observable. The system may use the backward trajectory to estimate the point-of-origin of the target. The system may also use the flow field measurements along the backward trajectory to classify the target. Target classification may be used to refine the point-of-origin estimate, to influence counter-fire or to adapt the flow field measurements.

01-15-2015

20130114067

HIGH DENSITY WIND VELOCITY DATA COLLECTION FOR WIND TURBINE - Methods and systems for collecting high-density wind velocity data for the inflow area of a wind turbine are presented. Wind turbines are provided with one or more wind velocity sensors that provide a plurality of wind velocity measurements to the turbine from various ranges and locations across the inflow. Sensors are proximate to the wind turbine. Sensors mounted on the turbine's nacelle work collaboratively to provide the wind velocity measurements. Sensors mounted on the turbine's hub spin with the turbine blades. Spatial and temporal wind mapping provides improved fidelity of data to the wind turbine control system.

05-09-2013

20130033696

PHYSICAL QUANTITY SENSOR AND PHYSICAL QUANTITY MEASURING UNIT - A physical quantity sensor includes a semiconductor laser for irradiating an object with a laser beam, and a laser driver for operating the semiconductor laser in such a way that a first oscillation period for which the oscillation wavelength increases and/or a second oscillation period for which the oscillation wavelength decreases is repetitively present. The sensor further includes a photodiode and a current-voltage conversion amplifying unit both for detecting an MHP containing an interference waveform formed by the self-coupling effect between the laser beam and the returning light beam from the object, a MHP extracting unit for measuring the period of the interference waveform contained in the output signal from the current-voltage conversion amplifying unit each time the interference waveform is inputted, and a computing unit for computing the displacement and/or the speed of the object from the measured individual period MHP extracting unit.

02-07-2013

20120162634

SPEED SENSOR - A sensor for sensing speeds, at least including a sensor unit, which has a radiation emitter element, a sensor element, a preliminary optical element and an evaluation circuit, a sensor housing, which has a leadframe, and a dirt guard unit, which includes a lens, wherein the sensor unit is in electrical contact with the leadframe of the sensor housing, and the lens of the dirt guard unit caps off the sensor housing as a cover.

06-28-2012

20130250276

Laser Wind Velocimeter With Multiple Radiation Sources - A system and method for measuring wind velocities are provided. A laser wind velocimeter with a radiation source includes a fiber laser. All optical signals, transmitted and received, are conveyed by optical fibers. An amplifier amplifies a source laser, which is then transmitted to one or more transceivers. The one or more transceivers, each projecting along a different axis, and each with a single optical fiber input/output interface act as both the transmission device to focus the radiation at a target region, and as the receiving system for collecting reflected radiation. The one or more transceivers transmit radiation to the target region. A portion of the reflected radiation collected by the receiving system is analyzed to determine the Doppler shift, which can me used to measure wind velocity

09-26-2013

20120092645

MULTI-LIDAR SYSTEM - An object of the present invention is to provide a method enabling measurement in a wider range than a conventional LIDAR system and capable of measuring airflow information, which is used to reduce shaking of an airframe when an aircraft collides with turbulence, in a shorter period, and a device having corresponding functions. A multi-LIDAR system according to the present invention includes at least two optical remote airflow measurement devices of a Doppler LIDAR system employing laser light that are provided in a fixed relative position relationship, has functions for emitting lasers of identical wavelengths from the respective devices and receiving scattered light by the respective devices, thereby improving redundancy with respect to defects, and improves a detectability by increasing an integration amount of respective measurement signals.

DEVICE AND METHOD FOR DETECTING AND MEASURING WIND FOR AN AIRCRAFT - The invention relates to a device for detecting and measuring wind at the front of an aircraft, said device comprising a lidar for the cyclic measurement of wind speeds at least a couple of measuring points located at the same distance, so-called measuring distance, from the nose of the aircraft. The invention is characterised in that it is suitable for measuring wind speeds, at each cycle, by means of the lidar, at a plurality of couples of measuring points (

SYSTEMS AND METHODS FOR SIGNAL PROCESSING IN OPTICAL IMAGING SYSTEMS - Systems, devices and methods of producing an image are provided. A electro-magnetic radiation source provides electro-magnetic radiation to a sample and a reference. A detector/interferogram unit produces at least one interferogram that is supplied to a signal processing unit. The signal processing unit extracts phase, magnitude, and/or polarization data from the supplied signals, and produces an image based on at least the extracted data.

09-06-2012

20110285984

Velocity measuring system - A laser Doppler velocimeter uses self-mixing amplification of backreflections from scatterers below the surface of a flow.

11-24-2011

20120242976

DEVICE FOR MEASURING WIND SPEED - A device comprises: an emitting element for emitting a laser beam, referred to as an emitted beam; a focusing element for focusing the emitted beam at a predetermined focal distance (D); a receiving element for receiving the emitted beam after being reflected by a particle in the air (

09-27-2012

20130215410

Velocity Measuring System - A laser Doppler velocimeter uses self-mixing amplification of backreflections from scatterers below the surface of a flow. A time domain signal is divided into segments that are roughly equal to a transit time of particles through a focus of a laser beam. The segments are connected to a frequency domain through the use of an FFT algorithm to produce frequency domain data segments. Signal-to-noise ratio is enhanced through signal processing techniques using the segments to produce a final enhanced signal spectrum.

08-22-2013

20110216307

High Density Wind Velocity Data Collection for Wind Turbine - Methods and systems for collecting high-density wind velocity data for the inflow area of a wind turbine are presented. Wind turbines are provided with one or more wind velocity sensors that provide a plurality of wind velocity measurements to the turbine from various ranges and locations across the inflow. Sensors are proximate to the wind turbine. Sensors mounted on the turbine's nacelle work collaboratively to provide the wind velocity measurements. Sensors mounted on the turbine's hub spin with the turbine blades. Spatial and temporal wind mapping provides improved fidelity of data to the wind turbine control system.

09-08-2011

20140132943

LOCALIZED DYNAMIC LIGHT SCATTERING SYSTEM WITH DOPPLER VELOCITY MEASURING CAPABILITY - A localized dynamic light scattering measurement system includes a beam displacer for splitting an incident beam having two orthogonal linearly polarized beam components with slightly different frequencies into two orthogonal linearly polarized output beams focused onto an object to be measured. The beam displacer cooperates with an iris to collect and recombine scattering beams each reversely backscattered at 180 degrees from the object so as to form a signal beam, which is polarized by a polarizer to produce two polarization components, thereby generating a heterodyne interference signal associated with the polarization components. A signal processing unit obtains measurement data on the object based on power spectrum or autocorrelation data corresponding to the heterodyne interference signal.

05-15-2014

20140132944

Methods, Systems and Computer Program Products for Processing Images Generated Using Fourier Domain Optical Coherence Tomography (FDOCT) - Methods, systems and computer program products for managing frequency domain optical coherence tomography (FDOCT) image resolution. A spectrum used to acquire an image of a subject is calibrated and default dispersion correction parameters are set. Default dispersion management parameters associated with a region of the image of the subject are also set. The image of the subject is acquires after setting the default dispersion correction parameters and the default dispersion management parameters. A quality of the acquired image is compared to a quality metric for the acquired image. The dispersion correction parameters are adjusted if the quality of the acquired image does not meet or exceed the quality metric for the acquired image. The acquired image is reprocesses based on the adjusted dispersion correction parameters. The steps of comparing, adjusting and reprocessing are repeated until the acquired image meets or exceeds the quality metric for the acquired image.

05-15-2014

20140160462

SYSTEM AND METHOD FOR ASSESSING THE FLOW OF A FLUID - A system for assessing the flow of a fluid. The system can include a light source, a fiber-optic system optically coupled to the light source, which is arranged to provide a reference beam and an observation beam, an optical detection system arranged to receive combined light from the reference beam and the observation beam and to provide detection signals, and a data processing system arranged to communicate with the optical detection system to receive the detection signals. The data processing system can be configured to use the detection signals to determine a speckle pattern corresponding to the fluid flow, wherein the speckle pattern includes a plurality of lines, and to calculate a correlation between adjacent lines perpendicular to the flow to determine at least one of a rate of the flow and a displacement of the flow.

06-12-2014

20110134412

AIRBORNE DEVICE FOR PREVENTING TURBULENCE-INDUCED ACCIDENTS - An object of the present invention is to provide a method for preventing turbulence-induced accidents that can expand a detection range to about 20 km without increasing the size of a device or increasing the energy consumption, can perform planar distribution monitoring of turbulence when the turbulence is detected in the flight direction and also can output a signal for autopilot steering input that decreases the fuselage shaking when the turbulence is difficult to avoid, as well as to provide a device having those functions. In the method for preventing turbulence-induced accidents according to the present invention, an optical remote airflow measurement device of a Doppler lidar system using a laser beam is used to routinely enable distant turbulence to be detected by fixing a laser emission course in a flight direction and taking a long integration time of a reception signal, and to enable planar distribution of the turbulence to be displayed when turbulence is detected, by scanning the laser emission course in a horizontal direction and switching an image display to a two-dimensional display.

06-09-2011

20080304045

Motion measurement and synchronication using a scanning interferometer with gratings - Indicating relative speed is disclosed. A first grating coupled to a first moving object is illuminated using a coherent light source to generate a first diffracted beam and a diffracted order beam. A second grating coupled to a second moving object is illuminated using the first diffracted beam and the second diffracted beam to generate a third diffracted beam and a fourth diffracted beam. The third diffracted beam and the fourth diffracted beam are measured. A relative speed of the first moving object with respect to the second moving object is indicated based at least in part on the measured third diffracted beam and the measured fourth diffracted beam.

12-11-2008

20090073417

COHERENT DOPPLER LIDAR - A coherent Doppler lidar which can oscillate high energy pulses and output laser beams in a longer wavelength range of 1.5 μm to the atmosphere is provided. The coherent Doppler lidar has a pulse laser an oscillation wavelength of which is controlled by means of injection locking of a seed light output from a master laser, wherein the pulse laser is a type in which a laser medium is disposed in a resonator, a pulse light of a predetermined repetition frequency is input to the laser medium as an excitation light, whereby pulse laser oscillation is generated in the resonator to output pulse laser beams from the resonator, and the laser medium being a type which has at least a region having Tm, Ho:YAG ceramics, and is excited by the excitation light to output pulse laser beams in 2 μm wavelength band.

03-19-2009

20090195771

PHYSICAL QUANTITY SENSOR AND PHYSICAL QUANTITY MEASURING METHOD - A physical quantity sensor has a semiconductor laser, a laser driver for providing, to the semiconductor laser, a driving electric current that is a waveform wherein the maximum portions and minimum portions of a triangle wave have been rounded; detecting means (a photodiode and a current-voltage converting amplifier) for detecting an electric signal that includes an interference waveform that is produced by the self-coupling effect between a laser beam that is emitted from the semiconductor laser and a return beam from a measurement object; and measuring means (a filter circuit, a counting device, and a calculating device) for calculating a physical quantity for the measurement object from interference waveform information.

08-06-2009

20090219507

SYSTEM AND METHOD FOR MOTION BASED VELOCITY DISCRIMINATION FOR DOPPLER VELOCIMETERS - A Doppler velocimeter apparatus and method of forming same. In one implementation a coherent light source is used for generating a beam of coherent light. An optical fiber receives the beam of coherent light. The optical fiber has an output face that is generally flat, thus enabling a first portion of the beam of coherent light to be reflected back on the optical fiber and to form a frequency offset, while a second portion of the beam of coherent light exits the optical fiber. A mechanism is used to move the output face of the optical fiber in an oscillating fashion so that the first portion of coherent light reflected back on the optical fiber produces an oscillating waveform that forms a frequency offset. An optical element receives the second portion of light from the face of the optical fiber and transmits it to a subject, and then receives a reflected optical signal back from the subject. The reflected optical signal, when mixed with the oscillating frequency offset, produces a Doppler shift that is dependent on the motion of the subject. A processing subsystem processes the mixed signal and determines the Doppler shift of the reflected signal.

09-03-2009

20090128800

Seismic Exploration - A method and apparatus for carrying our seismic exploration which comprises generating a seismic event; applying the seismic event to the earth's surface; detecting a response to the event, using an interferometer, in which there is relative motion between the earth's surface and the interferometer, the detected response including P-waves and S-waves in the earth's surface; and analysing the detected response; and in which: the detecting step comprises monitoring and recording the response to the seismic event in the form of movements of particles at the earth's surface, from a position spaced from the earth's surface, the detecting step being carried out over a response period, the response period being a predetermined period of time after the seismic event; and the analysing step comprises analysing the movements of particles at the earth's surface in the recorded response to the seismic event during the response period; the said relative motion having a total velocity V